Milecastle 22 (Portgate) was a milecastle of the Roman Hadrian's Wall. Its remains exist as a low, turf covered platform just east of the Portgate roundabout (junction of the A68 and B6318). The platform is on the east side, reducing to only a parch mark on the west side. Construction Milecastle 22 was assumed to be a long-axis milecastle, and had Type III gateways (only the north gateway has been identified). Such milecastles were thought to have been constructed by the legio VI Victrix who were based in Eboracum (York). The milecastle was across, but due to the location, the length of the other axis cannot be determined. It was constructed with Narrow Walls with a Standard B offset. Some time soon after construction of the milecastle, the north gateway was blocked by construction of a wall about thick. It has been suggested that this is due to the proximity of the Portgate, rendering the milecastle redundant as a means of passage through the wall. The curtain wall at this location was wide. Excavations and investigations 1930 – Excavation showed that the side walls were thick, but the north Wall had the normal thickness (). The internal width and the north gateway's type were also established. It was also discovered that the north gateway had been blocked. 1966 – English Heritage Field Investigation. The location was confirmed. It was also noted that the remains consisted of a slight earthen platform, considerably spread by cultivation. 1989 – English Heritage Field Investigation. It was noted that the milecastle survived as a squarish turf-covered platform, 0.5m high on the east side, but elsewhere as a parch mark only. 1992 – The eastern part of the south wall was unearthed, standing five courses high. Associated turrets Each milecastle on Hadrian's Wall had two associated turret structures. These turrets were positioned approximately one-third and two-thirds of a Roman mile to the west of the Milecastle, and would probably have been manned by part of the milecastle's garrison. The turrets associated with Milecastle 22 are known as Turret 22A and Turret 22B. Situated between Milecastle 22 and Turret 22A is a structure known as the Portgate. This was a major gateway, allowing Dere Street to pass through the line of the Hadrian's Wall. Turret 22A Turret 22A (Portgate) is (all but the south wall) buried beneath the Military Road. The south wall is under a fence